Locking mechanism for driving assembly, pallet stacker and control method

Abstract

The application discloses a locking mechanism for driving assembly, a tray stacker and a control method, and belongs to the technical field of tray stackers. The locking mechanism comprises a first lifting piece connected with the driving assembly, a second lifting piece which is installed on the first lifting piece in a liftable manner, a switching assembly connected between the first lifting piece and the second lifting piece, and a limiting assembly arranged between a vehicle frame and the second lifting piece. The switching assembly enables the first lifting piece and the second lifting piece to have two states of relative movement and relative fixation, and the limiting assembly is used for limiting the lowest descending height of the second lifting piece. The application can intelligently identify the tilting state of the vehicle and lock the downward movement of the driving system, effectively improves the lateral stability of the stacker when performing high-position operation on the inclined road, and reduces the risk of overturning.

Description

Technical Field

[0001] This invention relates to the field of pallet stacker technology, and particularly to a locking mechanism for a drive assembly, a pallet stacker, and a control method. Background Technology

[0002] Pallet stacker trucks (also known as pallet handling trucks) are commonly used material handling equipment in the warehousing and logistics field. They achieve the stacking and placement of pallets through the lifting of the mast and the lifting of the forks. To improve the adaptability of the drive wheels to the ground and the driving adhesion, the drive system of existing stacker trucks usually adopts a mid-mounted layout and is equipped with a suspension mechanism.

[0003] like Figure 1 As shown, in the prior art, the drive assembly of a pallet stacker is buoyantly mounted on the pallet stacker's frame via a suspension mechanism. The suspension mechanism includes an upper seat, a lower seat, a suspension seat, and a booster cylinder; the upper and lower seats are fixedly connected to the frame, and a guide shaft is provided between the upper and lower seats; the suspension seat is slidably connected to the guide shaft, and a floating spring is sleeved on the guide shaft above the suspension seat; the drive assembly is connected to the suspension seat, the booster cylinder is connected to the upper seat, and the output end of the booster cylinder is connected to the drive assembly via a booster spring; the drive assembly includes drive wheels.

[0004] The booster cylinder can push the booster spring downward to compress it, so that the drive wheel can get a greater ground load and avoid the problem of the pallet stacker slipping when fully loaded.

[0005] However, the existing structure has the following technical problems: when the pallet stacker is traveling on an inclined road, the floating spring and the booster spring will continuously apply an upward lifting force to the frame. This lifting force raises the center of gravity of the frame, thereby reducing the lateral stability of the frame. Especially when the mast lifting height is large, it will increase the risk of the pallet stacker tipping over. Summary of the Invention

[0006] Therefore, the purpose of this invention is to provide a locking mechanism for a drive assembly, a pallet stacker, and a control method to solve the problems mentioned in the background art.

[0007] In a first aspect, the present invention provides a locking mechanism for a drive assembly, comprising: A first lifting component connected to the drive assembly to float up and down with the drive assembly; A second lifting component that can be vertically mounted on the first lifting component; A switching component is connected to the first lifting member and the second lifting member, so that the first lifting member and the second lifting member have two states: relative movement and relative fixation. A limiting component is disposed between the frame and the second lifting member to limit the minimum descent height of the second lifting member.

[0008] As a further embodiment of the present invention, the first lifting component is a cylinder, and the second lifting component is a piston rod, wherein the piston rod is vertically mounted inside the cylinder.

[0009] As a further embodiment of the present invention, the two ends of the cylinder are sealed with end caps, and a sealing ring is fitted onto the piston rod. The outer dimensions of the sealing ring are adapted to the inner dimensions of the cylinder, and an upper cavity and a lower cavity are formed on the upper and lower sides of the sealing ring, respectively. The switching assembly includes: An oil passage connecting the upper and lower chambers, wherein the upper and lower chambers and the oil passage are all filled with hydraulic oil; A switch valve installed on an oil passage to control its on / off state.

[0010] As a further aspect of the present invention, the limiting component includes: A limiting seat that connects to the frame of a pallet stacker truck; A limiting rod is slidably connected within the limiting seat. The limiting rod is connected to the bottom of the second lifting component, and the top of the limiting rod has a radial protrusion.

[0011] As a further embodiment of the present invention, the limiting rod is provided with an elastic reset member so that the radial protrusion has an elastic reset force pointing towards the limiting seat.

[0012] As a further embodiment of the present invention, the elastic reset member is a reset spring sleeved on the limiting rod, the bottom of the limiting rod is provided with a support, and the two ends of the reset spring abut against the limiting seat and the support, respectively.

[0013] Secondly, the present invention provides a pallet stacker truck, which includes the locking mechanism as described above, and the drive assembly is buoyantly mounted on the frame of the pallet stacker truck via a suspension mechanism.

[0014] Thirdly, the present invention proposes a control method for controlling the pallet stacker truck as described above, comprising the following steps: Acquire the lifting height signal of the mast inside the pallet stacker truck and the tilt angle signal of the truck frame; When the lifting height signal reaches a preset height threshold and the tilt angle signal reaches a preset angle threshold, the switching component puts the first lifting member and the second lifting member in a relatively fixed state, so as to limit the minimum descent height of the drive assembly by limiting the minimum descent height of the second lifting member.

[0015] As a further aspect of the present invention, the preset height threshold is 1.8m and the preset angle threshold is 1.8°.

[0016] As a further embodiment of the present invention, the outer mast and inner mast of the pallet stacker are respectively provided with mast position sensors and sensing plates. The mast position sensors acquire the lifting height signal of the inner mast based on the sensing plate and compare the lifting height signal with a preset height threshold. When the lifting height signal reaches the preset height threshold, a first over-limit signal is issued. The pallet stacker is equipped with an angle sensor on its frame to acquire the tilt angle signal of the pallet stacker frame. The angle sensor compares the tilt angle signal with a preset angle threshold. When the tilt angle signal reaches the preset angle threshold, a second over-limit signal is issued. It also includes a controller, the input of which is connected to the gantry position sensor and the angle sensor, and the output of which is connected to the switching component. When the input of the controller receives the first over-limit signal and the second over-limit signal at the same time, the output of the controller sends a control signal to control the first lifting component and the second lifting component to switch to a relatively fixed state.

[0017] Compared with the prior art, the present invention has the following beneficial effects: 1. By setting up switching and limiting components, when the inner mast is raised to a high position and the frame is tilted, the switching component automatically fixes the first and second lifting components in a relatively fixed state, and the limiting component restricts the minimum descent height of the second lifting component, thereby limiting the minimum descent height of the drive assembly. At this time, the drive assembly cannot continue to move downward, eliminating the continuous upward lifting force exerted on the frame by the floating spring and the booster spring, preventing the frame's center of gravity from rising further, effectively suppressing the problem of decreased lateral stability caused by the increased center of gravity, and significantly reducing the risk of rollover under high-position tilting conditions.

[0018] 2. When the switching assembly brings the first and second lifting components to a relatively fixed state, the drive assembly, while unable to move downwards, has an upward floating clearance. When the drive wheel presses against a road bump, the drive assembly can drive the first and second lifting components and the limit rod upwards together, compressing the floating spring, the force-increasing spring, and the elastic reset component, preventing rollover caused by the road bump forcibly supporting the vehicle body. This allows the invention to improve lateral stability without sacrificing the drive assembly's adaptability to uneven road surfaces. Attached Figure Description Figure 1 This is a schematic diagram of the installation of a drive assembly in the prior art; Figure 2 This is a schematic diagram showing the installation location of the locking mechanism; Figure 3 This is a schematic diagram of the locking mechanism. Figure 4 This is a logic flowchart for a control method. Figure 5This is a schematic diagram of the controller's circuit connection.

[0019] Reference numerals: 100-Drive assembly, 11-Drive wheel, 200-Suspension mechanism, 21-Upper seat, 22-Lower seat, 23-Suspension seat, 24-Boosting cylinder, 25-Guide shaft, 26-Floating spring, 27-Force boosting spring, 300-Locking mechanism, 31-First lifting component, 311-End, 312-Upper cavity, 313-Lower cavity, 32-Second lifting component, 321-Sealing ring, 33-Switching assembly, 331-Oil passage, 332-Switch valve, 34-Limiting assembly, 341-Limiting seat, 342-Limiting rod, 3421-Radial protrusion, 3422-Elastic reset component, 3423-Support, 400-Pallet stacker. Detailed Implementation

[0020] To facilitate understanding of the present invention, a more comprehensive description will be given below with reference to specific embodiments. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of the disclosure of the present invention.

[0021] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

[0022] Example 1 like Figures 1-3 As shown, this embodiment proposes a locking mechanism for the drive assembly. The drive assembly 100 of the pallet stacker 400 is buoyantly mounted on the frame of the pallet stacker 400 via a suspension mechanism 200. The locking mechanism 300 includes a first lifting member 31, a second lifting member 32, a switching component 33, and a limiting component 34.

[0023] The first lifting component 31 is connected to the drive assembly 100 so as to float up and down with the drive assembly 100. Specifically, mounting seats are provided on the drive assembly 100 and the first lifting component 31 respectively, and the two mounting seats are fastened by bolts.

[0024] The second lifting member 32 is movably mounted on the first lifting member 31 so that the first lifting member 31 and the second lifting member 32 can move relative to each other in the vertical direction.

[0025] The switching component 33 is connected between the first lifting member 31 and the second lifting member 32, and is used to enable the first lifting member 31 and the second lifting member 32 to have two states: relative movement and relative fixation.

[0026] The limiting component 34 is disposed between the vehicle frame and the second lifting member 32 to limit the minimum descent height of the second lifting member 32.

[0027] When the inner mast of the pallet stacker 400 has a large lifting height and is traveling on an inclined road, the switching component 33 keeps the first lifting member 31 and the second lifting member 32 in a relatively fixed state. Because the limiting component 34 restricts the minimum lowering height of the second lifting member 32, the minimum lowering height of the first lifting member 31 is also limited, thereby limiting the minimum lowering height of the drive assembly 100 connected to the first lifting member 31. This prevents the drive assembly 100 from applying an upward lifting force, thereby lowering the center of gravity of the pallet stacker 400, improving the stability of the pallet stacker 400, and preventing the pallet stacker 400 from tipping over.

[0028] Example 2 The difference from Embodiment 1 is that this embodiment further discloses the specific technical features of the first lifting member 31, the second lifting member 32, the switching component 33, and the limiting component 34.

[0029] In this embodiment, the first lifting member 31 is a cylinder, and the second lifting member 32 is a piston rod, which is installed inside the cylinder in a liftable manner.

[0030] The cylinder is roughly a hollow cylindrical structure with an internal cavity for accommodating the piston rod. One end of the piston rod extends out of the cylinder and is connected to the limiting assembly 34. When the drive assembly 100 moves up and down, the cylinder moves together with the drive assembly 100, while the piston rod moves up and down relative to the cylinder.

[0031] The cylinder barrel is sealed at both ends by end caps 311 to ensure internal sealing. A sealing ring 321 is fitted onto the piston rod. The external dimensions of the sealing ring 321 are adapted to the internal dimensions of the cylinder barrel, allowing the sealing ring 321 to fit tightly against the inner wall of the cylinder barrel. The upper and lower sides of the sealing ring 321 form an upper cavity 312 and a lower cavity 313, respectively. That is, the sealing ring 321 divides the interior of the cylinder barrel into an upper cavity 312 located above the sealing ring 321 and a lower cavity 313 located below the sealing ring 321.

[0032] The switching assembly 33 includes an oil passage 331 and a switching valve 332. The oil passage 331 connects the upper chamber 312 and the lower chamber 313, and hydraulic oil is filled in the upper chamber 312, the lower chamber 313, and the oil passage 331. The switching valve 332 is installed on the oil passage 331 and is used to control the opening and closing of the oil passage 331.

[0033] When the switching valve 332 is opened, the oil passage 331 is in a connected state, and the hydraulic oil in the upper chamber 312 and the lower chamber 313 can flow freely through the oil passage 331. When the cylinder floats up and down with the drive assembly 100, the piston rod can rise and fall freely relative to the cylinder. The hydraulic oil on both sides of the sealing ring 321 flows between the upper chamber 312 and the lower chamber 313 through the oil passage 331, so that the first lifting member 31 and the second lifting member 32 are in a state of relative movement.

[0034] When the switching valve 332 is closed, the oil passage 331 is disconnected, and the hydraulic oil in the upper chamber 312 and the lower chamber 313 cannot flow through the oil passage 331. Because the hydraulic oil is incompressible, the piston rod cannot move relative to the cylinder, so that the first lifting member 31 and the second lifting member 32 are in a relatively fixed state.

[0035] The switching valve 332 is selected as a valve capable of controlling the on / off state of the oil passage 331. Specifically, in this embodiment, the switching valve 332 is selected as a solenoid valve.

[0036] The limiting assembly 34 includes a limiting seat 341 and a limiting rod 342. The limiting seat 341 is connected to the frame of the pallet stacker 400. Specifically, the limiting seat 341 can be fixed to the frame by welding or bolting. The limiting rod 342 is slidably connected inside the limiting seat 341 and is connected to the bottom of the second lifting member 32. Specifically, the upper end of the limiting rod 342 is fixedly connected to the end of the piston rod extending out of the cylinder by threaded connection or welding. The top of the limiting rod 342 has a radial protrusion 3421. When the radial protrusion 3421 contacts the limiting seat 341, the second lifting member 32 cannot continue to move downward, thereby limiting the minimum descent height of the second lifting member 32.

[0037] The limiting rod 342 is also provided with an elastic reset element 3422, so that the radial protrusion 3421 has an elastic reset force pointing towards the limiting seat 341. That is, when no external force is applied, the elastic reset element 3422 drives the limiting rod 342 to move downward, so that the radial protrusion 3421 abuts against the limiting seat 341. The elastic reset element 3422 is specifically a reset spring sleeved on the limiting rod 342. The bottom of the limiting rod 342 is provided with a support 3423, and the two ends of the reset spring abut against the limiting seat 341 and the support 3423 respectively. When the limiting rod 342 moves upward with the piston rod, the support 3423 compresses the reset spring, and the reset spring accumulates elastic potential energy; when the external force is removed, the reset spring releases the elastic potential energy, pushing the support 3423 to drive the limiting rod 342 and the piston rod to reset downward.

[0038] Example 3 like Figure 2As shown, this embodiment proposes a pallet stacker truck, including the locking mechanism 300 as described above, and the drive assembly 100 is buoyantly mounted on the frame of the pallet stacker truck 400 via the suspension mechanism 200.

[0039] By using a locking mechanism to suppress the decrease in lateral stability of pallet stackers caused by the rise in center of gravity, the risk of tipping over under high-altitude tilting conditions is significantly reduced.

[0040] Example 4 like Figure 4 and Figure 5 As shown, this embodiment proposes a control method for controlling the pallet stacker truck described above, including the following steps: S1, acquire the lifting height signal of the inner mast of the pallet stacker truck 400 and the tilt angle signal of the chassis.

[0041] S2, when the lifting height signal reaches a preset height threshold and the tilt angle signal reaches a preset angle threshold, the switching component 33 puts the first lifting member 31 and the second lifting member 32 in a relatively fixed state, so as to limit the minimum descent height of the drive assembly 100 by limiting the minimum descent height of the second lifting member 32.

[0042] When the pallet stacker 400 is traveling on a flat road surface and the inner mast is at a low lifting height, the vehicle has good stability. At this time, the switch valve 332 is open, the oil passage 331 is connected, and the first lifting component 31 and the second lifting component 32 can move freely relative to each other. The drive assembly 100 floats up and down normally with the undulations of the road surface through the suspension mechanism 200 to adapt to different road surface requirements.

[0043] Specifically, under the action of the return spring, the radial protrusion 3421 of the limit rod 342 contacts the limit seat 341, and the piston rod remains relatively fixed; the cylinder moves up and down with the drive assembly 100, and the hydraulic oil flows back and forth between the upper chamber 312 and the lower chamber 313 through the oil passage 331.

[0044] When the inner mast rises to a preset height threshold (e.g., 1.8 meters above the ground) and the vehicle is traveling on an inclined road surface with a left-right tilt angle reaching a preset angle threshold (e.g., 1.8°), the control system determines that the vehicle is at risk of tipping over. At this time, the switch valve 332 closes, the oil passage 331 disconnects, and the first lifting component 31 and the second lifting component 32 are in a relatively fixed state. Specifically, after the solenoid valve closes, the hydraulic oil in the upper chamber 312 and the lower chamber 313 cannot flow, and the piston rod is locked in the cylinder and cannot move. Since the limiting seat 341 of the limiting assembly 34 is fixed on the frame, and the radial protrusion 3421 of the limiting rod 342 is blocked by the limiting seat 341, the locking mechanism 300 is fixed to the drive assembly 100 by the mounting seat, and the drive assembly 100 cannot continue to move downward. At this point, the load wheel and auxiliary wheel on one side of the vehicle body form a tilting rotation axis. The torque generated by the vehicle body's own weight counteracts the tilting torque generated by the inner mast and cargo center of gravity exceeding the tilting rotation axis, thereby preventing the vehicle body from tipping over and improving the vehicle's lateral stability.

[0045] When the inner mast rises to a preset height threshold and the vehicle is traveling on an inclined road surface, and the drive wheel 11 presses against a road bump, the relative positions of the cylinder and piston rod of the drive assembly 100 and the locking mechanism 300 are fixed because the first lifting member 31 and the second lifting member 32 are in a relatively fixed state. There is a certain gap between the radial protrusion 3421 of the limiting rod 342 and the limiting seat 341. When the drive wheel 11 presses against the bump, the road bump pushes the drive wheel 11 upwards, causing the drive assembly 100 to move upwards as a whole, driving the cylinder and piston rod upwards together. The limiting rod 342 slides upwards within the limiting seat 341, compressing the floating spring 26, the force-increasing spring 27, and the return spring. This allows the drive assembly 100 to float upwards even in the locked state, avoiding the risk of rollover caused by the road bump forcibly supporting the vehicle body. After the bump passes, the drive assembly 100 and the locking mechanism 300 return to their original positions under the action of the floating spring 26, the force-increasing spring 27, and the return spring.

[0046] When the inner mast lifting height is lower than the preset height threshold, the vehicle stability safety factor is high. In order to improve the working efficiency and the adhesion of the drive wheel 11, the switch valve 332 of the switching component 33 remains open, the locking mechanism 300 does not work, and the drive assembly 100 floats normally.

[0047] It also includes a gantry position sensor, an angle sensor, and a controller.

[0048] A gantry position sensor is installed on the outer gantry of the pallet stacker 400, and acquires the lifting height signal of the inner gantry of the pallet stacker 400 based on a sensing plate installed on the inner gantry. The gantry position sensor can be a proximity switch, photoelectric sensor, or displacement sensor, etc. The gantry position sensor compares the lifting height signal with a preset height threshold. When the lifting height signal reaches the preset height threshold, the gantry position sensor is triggered and continuously sends a first over-limit signal to the controller.

[0049] An angle sensor is installed on the frame of the pallet stacker 400 to acquire the left and right tilt angle signals of the frame in real time. The angle sensor can be a tilt sensor, which can detect the left and right tilt angle of the frame relative to the horizontal plane. The angle sensor compares the tilt angle signal with a preset angle threshold. When the tilt angle signal reaches the preset angle threshold, it continuously sends a second over-limit signal to the controller.

[0050] The input terminal of the controller is electrically connected to the gantry position sensor and the angle sensor, and the output terminal of the controller is connected to the switching component 33 (e.g., a solenoid valve). When the input terminal of the controller receives the first over-limit signal and the second over-limit signal at the same time, the output terminal of the controller sends a control signal to control the first lifting component (31) and the second lifting component (32) to switch to a relatively fixed state. Conversely, if the first over-limit signal and the second over-limit signal are not received at the same time (only one over-limit signal is received or no over-limit signal is received), the output terminal of the controller sends a control signal to control the first lifting component (31) and the second lifting component (32) to switch to a relatively moving state.

[0051] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0052] The above embodiments merely illustrate several implementation methods of the present invention, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A locking mechanism for driving an assembly, characterized in that, include: A first lifting element (31) is connected to the drive assembly (100) to float up and down with the drive assembly (100). A second lifting component (32) is mounted on the first lifting component (31) in a height-adjustable manner; A switching component (33) is connected to the first lifting member (31) and the second lifting member (32) so that the first lifting member (31) and the second lifting member (32) have two states: relative movement and relative fixation. A limiting component (34) is disposed between the frame and the second lifting member (32) to limit the minimum descent height of the second lifting member (32).

2. The locking mechanism for the drive assembly according to claim 1, characterized in that, The first lifting component (31) is a cylinder, and the second lifting component (32) is a piston rod, which is installed inside the cylinder in a liftable manner.

3. The locking mechanism for the drive assembly according to claim 2, characterized in that, The cylinder is sealed at both ends by end caps (311), and a sealing ring (321) is fitted onto the piston rod. The outer dimensions of the sealing ring (321) are adapted to the inner dimensions of the cylinder. The upper and lower sides of the sealing ring (321) form an upper cavity (312) and a lower cavity (313), respectively. The switching assembly (33) includes: An oil passage (331) connecting the upper cavity (312) and the lower cavity (313) is provided, and the upper cavity (312), the lower cavity (313) and the oil passage (331) are all filled with hydraulic oil; A switching valve (332) is installed on the oil passage (331) to control its on / off state.

4. The locking mechanism for the drive assembly according to claim 1, characterized in that, The limiting component (34) includes: Limit seat (341) connected to the frame of the pallet stacker (400). A limiting rod (342) is slidably connected to the limiting seat (341). The limiting rod (342) is connected to the bottom of the second lifting member (32). The top of the limiting rod (342) is provided with a radial protrusion (3421).

5. The locking mechanism for the drive assembly according to claim 4, characterized in that, The limiting rod (342) is provided with an elastic reset member (3422) so that the radial protrusion (3421) has an elastic reset force pointing towards the limiting seat (341).

6. The locking mechanism for the drive assembly according to claim 5, characterized in that, The elastic reset component (3422) is a reset spring sleeved on the limiting rod (342). The bottom of the limiting rod (342) is provided with a support (3423). The two ends of the reset spring abut against the limiting seat (341) and the support (3423) respectively.

7. A pallet stacker truck, characterized in that, It includes a locking mechanism as described in any one of claims 1-6, wherein the drive assembly (100) is buoyantly mounted on the frame of the pallet stacker (400) via a suspension mechanism (200).

8. A control method, characterized in that, It is used to control the pallet stacker as described in claim 7, comprising the following steps: Acquire the lifting height signal and the tilt angle signal of the inner mast of the pallet stacker truck (400); When the lifting height signal reaches a preset height threshold and the tilt angle signal reaches a preset angle threshold, the switching component (33) puts the first lifting member (31) and the second lifting member (32) in a relatively fixed state, so as to limit the minimum descent height of the drive assembly (100) by limiting the minimum descent height of the second lifting member (32).

9. The control method according to claim 8, characterized in that, The preset height threshold is 1.8m, and the preset angle threshold is 1.8°.

10. The control method according to claim 8, characterized in that, The pallet stacker (400) is equipped with a mast position sensor and a sensing plate on its outer mast and inner mast respectively. The mast position sensor obtains the lifting height signal of the inner mast based on the sensing plate and compares the lifting height signal with a preset height threshold. When the lifting height signal reaches the preset height threshold, a first over-limit signal is issued. An angle sensor is provided on the frame of the pallet stacker (400) to obtain the tilt angle signal of the pallet stacker (400) frame. The angle sensor compares the tilt angle signal with a preset angle threshold. When the tilt angle signal reaches the preset angle threshold, a second over-limit signal is issued. It also includes a controller, the input of which is connected to the gantry position sensor and the angle sensor, and the output of which is connected to the switching component (33). When the input of the controller receives the first over-limit signal and the second over-limit signal at the same time, the output of the controller sends a control signal to control the first lifting component (31) and the second lifting component (32) to switch to a relatively fixed state.

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